Air pollution increases breast cancer risk

Air pollution increases breast cancer risk | Image Credit: © Андрей Трубицын - © Андрей Трубицын - stock.adobe.com.

Residing in an area with high levels of air pollution is associated with increased breast cancer risk, according to recent research from the National Institute of Environmental Health Sciences (NIEHS) and the National Cancer Institute (NCI).

Data was obtained from the NIH-AARP Diet and Health Study, including over 500,000 participants residing in California, Florida, Pennsylvania, New Jersey, North Carolina, Louisiana, Detroit, or Atlanta from 1995 to 1996.The mean age of participants was 62 years, with most being non-Hispanic White.

Particulate matter was described as a mix of solid particles and liquid droplets in the air. Sources of particulate matter include combustion processes such as coal or oil, motor vehicle exhaust, industrial emissions, and wood smoke or vegetation burning.

Investigators evaluated particulate matter pollution 2.5 microns in diameter or smaller (PM2.5) in the study. This type of particulate matter is small enough to breathe deep into the lungs. The estimated annual mean historical PM2.5 concentrations for each participant’s residence was evaluated.

There were 15,870 cases of breast cancer across the 20 years patients followed. Women with higher PM2.5 levels near their home before enrolling in the study had a higher average incidence of breast cancer. 

“We observed an 8% increase in breast cancer incidence for living in areas with higher PM2.5 exposure, said Alexandra White, PhD, lead author and head of the Environment and Cancer Epidemiology Group at NIEHS.

“Although this is a relatively modest increase, these findings are significant given that air pollution is a ubiquitous exposure that impacts almost everyone,” White added. “These findings add to a growing body of literature suggesting that air pollution is related to breast cancer.”

Estrogen receptor-positive (ER+) and -negative (ER-) tumors were separately evaluated to determine the association between air pollution and breast cancer based on tumor type. PM2.5 was associated with increased ER+ breast cancer incidence, but not ER- breast cancer incidence, indicating PM2.5 may impact breast cancer through a biologic pathway of endocrine disruption.

“The ability to consider historic air pollution levels is an important strength of this research,” said Rena Jones, PhD, senior author and principal investigator of the study at NCI. “It can take many years for breast cancer to develop, and, in the past, air pollution levels tended to be higher, which may make previous exposure levels particularly relevant for cancer development.”

The study had a limited ability to investigate the differences in the association between air pollution and breast cancer across study areas. Investigators recommended future studies to explore how regional differences in air pollution impact breast cancer incidence.

Reference

High levels of particulate air pollution associated with increased breast cancer incidence. National Institutes of Health. September 11, 2023. September 18, 2023. https://www.nih.gov/news-events/news-releases/high-levels-particulate-air-pollution-associated-increased-breast-cancer-incidence